#include <urcu-bp.h>
#include <ust/marker.h>
+#include <ust/tracectl.h>
#include "tracer.h"
#include "usterr.h"
#include "ustcomm.h"
return (void *)1;
}
}
+ else if(!strcmp(recvbuf, "trace_create")) {
+ DBG("trace create");
+
+ result = ltt_trace_setup(trace_name);
+ if(result < 0) {
+ ERR("ltt_trace_setup failed");
+ return (void *)1;
+ }
+
+ result = ltt_trace_set_type(trace_name, trace_type);
+ if(result < 0) {
+ ERR("ltt_trace_set_type failed");
+ return (void *)1;
+ }
+
+ result = ltt_trace_alloc(trace_name);
+ if(result < 0) {
+ ERR("ltt_trace_alloc failed");
+ return (void *)1;
+ }
+
+ inform_consumer_daemon(trace_name);
+ }
else if(!strcmp(recvbuf, "trace_start")) {
DBG("trace start");
/* Ensure markers are initialized */
init_markers();
- /* In case. */
+ /* FIXME: When starting early tracing (here), depending on the
+ * order of constructors, it is very well possible some marker
+ * sections are not yet registered. Because of this, some
+ * channels may not be registered. Yet, we are about to ask the
+ * daemon to collect the channels. Channels which are not yet
+ * registered will not be collected.
+ *
+ * Currently, in LTTng, there is no way to add a channel after
+ * trace start. The reason for this is that it induces complex
+ * concurrency issues on the trace structures, which can only
+ * be resolved using RCU. This has not been done yet. As a
+ * workaround, we are forcing the registration of the "ust"
+ * channel here. This is the only channel (apart from metadata)
+ * that can be reliably used in early tracing.
+ *
+ * Non-early tracing does not have this problem and can use
+ * arbitrary channel names.
+ */
ltt_channels_register("ust");
result = ltt_trace_setup(trace_name);
* the new process, anytime a process whose memory is not shared with
* the parent is created. If this function is not called, the events
* of the new process will not be collected.
+ *
+ * Signals should be disabled before the fork and reenabled only after
+ * this call in order to guarantee tracing is not started before ust_fork()
+ * sanitizes the new process.
*/
-void ust_fork(void)
+static void ust_fork(void)
{
struct blocked_consumer *bc;
struct blocked_consumer *deletable_bc = NULL;
inform_consumer_daemon("auto");
}
+void ust_before_fork(ust_fork_info_t *fork_info)
+{
+ /* Disable signals. This is to avoid that the child
+ * intervenes before it is properly setup for tracing. It is
+ * safer to disable all signals, because then we know we are not
+ * breaking anything by restoring the original mask.
+ */
+ sigset_t all_sigs;
+ int result;
+
+ /* FIXME:
+ - only do this if tracing is active
+ */
+
+ /* Disable signals */
+ sigfillset(&all_sigs);
+ result = sigprocmask(SIG_BLOCK, &all_sigs, &fork_info->orig_sigs);
+ if(result == -1) {
+ PERROR("sigprocmask");
+ return;
+ }
+}
+
+/* Don't call this function directly in a traced program */
+static void ust_after_fork_common(ust_fork_info_t *fork_info)
+{
+ int result;
+ sigset_t orig_sigs;
+
+ /* Restore signals */
+ result = sigprocmask(SIG_SETMASK, &fork_info->orig_sigs, NULL);
+ if(result == -1) {
+ PERROR("sigprocmask");
+ return;
+ }
+}
+
+void ust_after_fork_parent(ust_fork_info_t *fork_info)
+{
+ /* Reenable signals */
+ ust_after_fork_common(fork_info);
+}
+
+void ust_after_fork_child(ust_fork_info_t *fork_info)
+{
+ /* First sanitize the child */
+ ust_fork();
+
+ /* Then reenable interrupts */
+ ust_after_fork_common(fork_info);
+}
+